i didn't know about the ability to chop a page into multiple pages that might help. And yes kindle does have a landscape option and it does help, but only so much.

It seems like the hardest documents to convert are technical computer manuals with a lot of diagrams and side notes, unfortunately this is what i tend to read the most.

what do you think is the most reliable conversion method though ?

PDF is an end format. It is very difficult to predict how a conversion will go as the total design is around a fixed page size. Some PDF's may convert ok so you can always try that route but don't be surprised when there are problems. PDF viewers that have zoom work the best but cropping can help and it the best for stubborn documents. Good Luck.

One trick for PDF is when it won't convert well try printing it to PDF. The new PDF may convert better.